(1) Field of the Invention
This invention relates to space frames.
(2) Brief Description of the Prior Art
Where constructions of shallow depth are required to be erected over wide spans with a minimum number of supports and with a minimum of elastic movement under load, space frames are usually considered most appropriate. In most cases a space frame is of double-layer type, comprising upper and lower grids of longitudinal and lateral members or chords, the junctions of chords, or nodes, of the upper and lower grid being interconnected by oblique web members or struts. Usually the lower grid is displaced both longitudinally and laterally relative to the upper grid so that each node of the lower grid is exuidistant from four nodes of the upper grid, and is connected to them by four oblique struts. In some space frames, however, the nodes of the lower grid are directly below those of the upper grid so that the axes of the oblique struts are in the axes of the chords they interconnect, and additional vertical struts may interconnect corresponding nodes of the two grids.
Space frames may be modified for the construction of tunnel-vaulted, rather than flat, structures.
A disadvantage of many space frame constructions presently in use is that expensive connectors are used to interconnect chord and strut members at each node, and the fixture of the members to the connectors requires a good deal of time and skilled labour.